Conventionally, there are known an apparatus and a method for detecting an object on the basis of image information as an apparatus and a method for detecting an object, respectively (e.g., refer to Patent document 1). The detection apparatus according to Patent document 1 learns information (e.g., feature amount) about an object to be detected (e.g., face) included in the image information, and configures plural homogeneous classifiers according to the learning result. The plural homogeneous classifiers are configured so as to have different degrees of detection accuracy for the object to be detected by the change of the number of the feature amounts, for example. The apparatus according to Patent document 1 configures one detector by connecting the plural homogeneous classifiers in cascade so as to gradually provide higher detection accuracy of each of the homogeneous classifiers toward the end of the processing. The apparatus according to Patent document 1 inputs the image information of an image to be determined into the detector and causes the homogeneous classifiers configuring the detector to operate in the cascade order, and then determines that the object to be detected has been detected from the determination image information only when all the homogeneous classifiers have detected the object to be detected. Here, when one of the plural homogeneous classifiers configuring the detector has determined that the determination image information does not include the feature amount of the object to be detected, the apparatus according to Patent document 1 does not perform the processing to be performed after the processing in the homogeneous classifiers and determines that the object to be detected is not detected from the determination image information.